Title of Paper:Catalytic oxygenation of dibenzothiophenes to sulfones based on Fe-III porphyrin complex

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Date of Publication:2011-04-15

Journal:APPLIED CATALYSIS A-GENERAL

Included Journals:SCIE、EI

Volume:396

Issue:1-2

Page Number:101-106

ISSN No.:0926-860X

Key Words:Iron tetra-(2-chlorophenyl) porphyrin chloride; Oxygenation; Dibenzothiophene

Abstract:Fe-III porphyrin complexes as biomimetic catalysts display remarkable activity in the oxidation of dibenzothiophenes (DBTs) to the corresponding sulfones, in the absence of co-reductants or sacrificial agents, for deep desulfurization. The influence of the reaction conditions on the catalytic oxygenation was investigated. UV-vis spectra of Fe-III porphyrin complexes under various reaction conditions revealed that temperature was a vital factor for the catalyst's lifetime. However, catalyst decomposition was not caused by thermal self-destruction but by oxygenation at high temperatures. The Fe-III porphyrin complex was decomposed partly during the oxygenation, which was retarded by adding carbazole (CAR) to the reaction medium. Fe-III porphyrins, substituted with electron-withdrawing groups (-Cl), showed higher efficiency than electron-donating groups (-OH). Radical scavenging experiments demonstrated that the oxygenation catalyzed by the Fe-III porphyrin complex was not a free-radical reaction. Based upon the DBTs' concentrations, obtained by gas chromatography, the catalytic oxygenation can be treated kinetically as a first-order reaction. Finally, a mechanism involving a two-step nucleophilic addition was proposed for the oxygenation. (C) 2011 Elsevier B.V. All rights reserved.